1. Field of the Invention
The present invention relates to a mini jack for use with an electrical apparatus, and particularly to a mini jack for electrically contacting a pin plug to a circuit board on which the mini jack is mounted.
2. The Prior Art
Conventional electrical jacks for receiving an external pin plug from an audibly or visibly input/output device, are equipped with a plurality of grounding contacts and signal contacts wherein each grounding contact is adapted to electrically connect the pin plug to a circuit board on which the electrical jack is mounted for providing the electrical engagement between the electrical jack and pin plug with a grounding protection when noise interference exists therein. A contact portion of such a grounding contact is generally fabricated by stamping to have a bifurcate configuration which is defined with a pair of coplanar and opposite arms and a narrow slot defined therebetween as disclosed in U.S. Pat. No. 4,846,719 and Taiwan Patent Application Nos. 78,204,014 and 78,204,013, however, the arms lack appropriate elasticity therein. Therefore, when the pin plug is forcedly inserted into the electrical jack to be clamped between the pair of arms of the contact portion, inner shear edges formed on each of the arms of the grounding contact via stamping process may directly scrape a plating layer on a surface of the pin plug or a permanent deformation is happened in the arms if the dimension of the narrow slot between the arms is less than that of the pin plug. Furthermore, the contact area on the shear edges of the arms for contacting with the pin plug is too small to ensure a sufficient and reliable engagement therewith.
Accordingly, to resolve the above disadvantages, an object of the present invention is to provide a mini jack which has a grounding contact with a spring arm functioning as a cantilever beam via a bending process for providing the connection with a pin plug with a higher elasticity thereby preventing the spring arm from being the permanently deformed.
Another object of the present invention is to provide a mini jack which has a grounding contact with a curved contact section via a bending process for providing a smooth contact area thereon, thereby prohibiting the grounding contact from directly scraping or damaging a plating layer on an outer surface of a pin plug.
A further object of the present invention is to provide a grounding contact which defines a body portion and a spring arm perpendicularly bent from the body portion for preventing influencing the solder between the grounding contact and a circuit board on which the mini jack is mounted when the spring arm is elastically pressed by a pin plug.